scholarly journals The determination of potential ammonification in soil by arginine method

2002 ◽  
Vol 47 (2) ◽  
pp. 129-135
Author(s):  
Mirjana Kresovic ◽  
V. Licina
Keyword(s):  
Forest Soil ◽  
Ph Value ◽  
Correlation Coefficients ◽  
Brown Forest Soil ◽  
Available Nitrogen ◽  
Organic C ◽  
Arginine Ammonification ◽  
Different Doses ◽  
Properties Of Soil

In this paper investigations were carried out on two soil types (vertisol and brown forest soil) with different doses of applied N-fertilizer: diameter, N60 N90; N120 and N250. The potential ammonification in soil was obtained by arginine method. The following properties of soil were determined: pH value organic C, available NH4-N and mobile-Al. The pH value in vertisol was 3.75-4.07; mobile-Al was 0.67-4.90 mg/100g; % organic C 1.38-1.46 and the content of available nitrogen was 4.4-11.2 ppm. The amount of released NH4-N by arginine ammonification in this soil type was very low [(-0.12)-0.27mg/g-1h-1]. Correlation coefficients between released NH4-N from arginine and soil pH were (-0.96*), mobile Al - (-0.99**), applied fertilizer doses - (-0.95*). In brown forest soil the amount of released NH4-N by arginine ammonification was greater than in vertisol, ranging from 3.16 to 7.11mg/g-1h-1. Correlation coefficients between soil properties and released NH4-N from arginine were not statistically significant.

Optimization of sol-gel based fibre-optic cholinesterase biosensor for the determination of organophosphorus pesticides

2000 ◽  
Vol 42 (7-8) ◽  
pp. 283-290 ◽  
Author(s):  
H.-C. Tsai ◽  
R.-A. Doong
Keyword(s):  
Fiber Optic ◽  
Ph Value ◽  
Rapid Determination ◽  
Organophosphorus Pesticides ◽  
Sol Gel ◽  
Neutral Red ◽  
Fluorescent Indicators ◽  
Low Leakage ◽  
Fiber Optic System

A sol-gel based fiber-optic biosensor with acetylcholinesterase as the biorecognition element has been developed for the rapid determination of organophosphorus pesticides. Nine fluorescent indicators, acridine, acridine orange, neutral red, DAPI, rhodamine B, fluorescein, umbelliferone, FITC on celite and FITC-dextran, have been examined to optimize the fiber-optic system. Results showed that acridine and FITCs were sensitive to the change of pH value caused by the enzyme-substrate catalysis reaction. However, the sensitivity of acridine was 260 times lower than that of FITCs. Higher toxicity of acridine to acetylcholinesterase than FITC was also observed. Moreover, the high-molecular-weight FITC-dextran showed low leakage rate when immobilizing using sol-gel technology, showing that the FITC-dextran was a suitable pH sensitive fluorescent indicator for the OPPs biosensor. The response of the fiber-optic biosensor to the substrate, acetylcholine, was highly reproducible (RSD=3.5%). A good linearity of acetylcholine in the range from 0.5 to 20 mM was also obtained (R2=0.98). Furthermore, a 30% inhibition can be achieved in 30min when 152 ppb paraoxon was added into the system. The results show the possibility for real-time determination of organophosphorus pesticides by using the biosensor developed in this study.

scholarly journals Preparation and certification of reference materials, brown forest soil (JSAC 0401) and volcanic ash soil (JSAC 0411) for the analysis of trace metals.

2002 ◽  
Vol 51 (4) ◽  
pp. 269-279 ◽  
Author(s):  
Shin-ichi YAMASAKI ◽  
Shoji HIRAI ◽  
Masataka NISHIKAWA ◽  
Yoshinori TAKATA ◽  
Akira TSURUTA ◽  
...  
Keyword(s):  
Trace Metals ◽  
Forest Soil ◽  
Reference Materials ◽  
Volcanic Ash ◽  
Brown Forest Soil ◽  
Volcanic Ash Soil

Compartmental transfer of mercury released from amalgam

1997 ◽  
Vol 16 (11) ◽  
pp. 667-672 ◽  
Author(s):  
S. Halbach ◽  
L. Kremers ◽  
H. Willruth ◽  
A. Mehl ◽  
G. Welzl ◽  
...  
Keyword(s):  
Oral Cavity ◽  
Urinary Excretion ◽  
Total Mercury ◽  
Excretion Rate ◽  
Absorbed Dose ◽  
Correlation Coefficients ◽  
Urinary Excretion Rate ◽  
Amalgam Fillings

The number of amalgam-covered surfaces and the occlusal area of the fillings, the concentrations of total mercury in plasma, erythrocytes and urine, the urinary excretion rate, and the absorbed daily doses estimated by two separate methods from intra-oral Hg emission were determined in 29 volunteers with a low amalgam load. The transfer ofHg from the fillings via the oral cavity and blood to urinary excretion was evaluated by multiple correla tions between these variables. In addition, the combina tion of variables most representative of the entire compartmental transfer of amalgam Hg was determined. Urinary excretion (1), Hg concentration in plasma (2) and absorbed dose (3) were most closely correlated to each other, followed by correlations with the variables of the fillings (4). Correlation coefficients were 0.75 for variables 1 vs 2 and 2 vs 3, and 0.49 for variables 3 vs 4. It was concluded that variables 1-3 best reflected the transfer of mercury from amalgam fillings throughout the organism and that they were relatively insensitive to dietary mercury. The determination of total mercury in plasma and of its urinary excretion rate appears, under practical aspects, most suitable for the investigation of Hg uptake from amalgam.

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